To a suspension of lithium aluminum hydride (37 mg, 0.98 mmol) in tetrahydrofuran (4 mL) was added a solution of methyl 2-{[1-(cyclopropylmethyl)-2-(2,2-dimethylpropyl)-1H-benzimidazol-5-yl]sulfonyl}-2-methylpropanoate (Step G, 400 mg, 0.98 mmol) in tetrahydrofuran (4 mL) at 0° C. After stirring for 3 h at 0° C., the mixture was quenched with potassium fluoride (170 mg, 2.96 mmol) and sodium sulfate decahydrate (1.26 g, 3.92 mmol) at 0° C., filtered through a pad of celite and concentrated. The resulting residue was purified by column chromatography on silica gel (hexane:ethyl acetate=1:1 as eluent) to afford the title compound (345 mg, 93%) as a white amorphous solid.
